1. Field of the Invention
The present invention relates to a technique of controlling an image processing apparatus including a document reader unit capable of reading a series of document sheets on a part-by-part basis, and an image output unit for outputting image data acquired via the reading performed by the document reader unit.
2. Description of the Related Art
A digital multifunction device having a printer function, a scanner function, a facsimile function, etc., is known in the art. In such digital multifunction devices, or a similar image processing apparatus, image data obtained via the scanning function, facsimile function, or PDL data received from a host computer can be stored in a storage device of the digital multifunction device. A desired image data can later be read from the storage device and printed.
In using digital multifunction devices, when a given document set includes a series of sheets that is greater than the number of sheets than can be placed on a document tray of the digital multifunction device, it is impossible to read all of the sheets at a single time. One known technique of circumventing this problem is to read the given document set on a part-by-part basis, and then combine the separately read parts into a single set of document image data. Reading of the document set on a part-by-part basis can be accomplished either by using the digital multifunction device's automatic document feeder or by placing each sheet of the document set on the document platen of the digital multifunction device.
There are several methods for checking to ensure that reading of all the sheets of the document set was successful, i.e., that all the sheets were read correctly, that all the expected sheets are present, or that no extraneous sheets are present. In one case, a hard copy of the document set is obtained by performing a test print after reading and storing of all the sheets of the document set has been completed. The hard copy is then reviewed to ensure that the reading was successfully performed.
Another case involves image data that has been stored in the digital multifunction device's storage device after it was obtained by scanning an original document. In this case, it is possible to electronically preview the stored image data and perform editing such as deletion or insertion of a page/sheet. However, previewing of the image can only be performed after the entire document has been scanned and stored. The ability to preview the image during the actual scanning operation is not available.
It is currently known that digital copiers are capable of including a function that when an error is detected during a reading operation, a preview image of the page corresponding to the reading error can be displayed. That is, a preview image is available during the reading operation. This enables a user to confirm whether the page corresponding to the reading error is acceptable or not, which provides the user with an opportunity to decide whether to continue the copying operation without re-reading the page corresponding to the reading error. However, this particular feature of enabling previewing during the reading operation is a very limited one. Specifically, the copier is typically only stores one to two pages at any given time during the reading operation. Thus, the entire reading operation must still be completed in order for a user to be able to preview the entire document.
Specific examples of such known techniques may be found, for example, in Japanese Laid-Open Patents 5-292268, 2000-184110, or 10-200677 or Japanese Patent 3111621.
As shown above, conventional digital multifunction devices do not provide the feature of enabling a user to preview the entire image date of a document until all sheets of the document have been read. Even in the case where such a feature is provided, it is a very limited feature and is only available during a copying operation. If an error is detected after all the sheets have been read, it may be necessary to re-read a particular sheet or all the sheets. Therefore, after a plurality of document sheets are separately read as multiple batches of read image, the obtained image data is combined together and output as a series of document set, previewing is impossible until scanning of all document sets are completed. This is very inconvenient and inefficient for users.
Confirmation by reading a document sheet on the platen and printing the resultant image data is also very inconvenient for a user, particularly when a given document set includes a large number of pages. In addition, an extra number of sheets are necessary for confirmation.